Kanshi Komatsu

Is Atrial Fibrillation Resulting From Rheumatic Mitral Valve Disease a Proper Indication for the Maze Procedure

BACKGROUND There are a few patients without detectable atrial contraction despite restoration of atrial rhythm after the maze procedure for atrial fibrillation (AF) associated with mitral valve disease. METHODS From January 1995 to March 1997, 29 consecutive patients with AF associated with mitral valve disease underwent our modified maze procedure combined with mitral or other valve operations. The causes of mitral valve disease were rheumatic mitral stenosis (n = 22) and nonrheumatic mitral regurgitation (n = 7). The 17 patients with postoperative atrial rhythm were divided into group I with rheumatic mitral stenosis (n = 10), and group II with mitral regurgitation of nonrheumatic origins (n = 7). RESULTS Seventeen patients regained atrial rhythm, 2 patients had junctional rhythm, and another 10 remained in AF. Between the group of patients with restoration of atrial rhythm and that of patients remaining in AF, significant differences were found in the percentage with rheumatic disease, history of AF, and maximum f-wave voltage. The postoperative peak velocity of the atrial filling wave to peak velocity of early filling wave ratio for the left atrium measured using Doppler echocardiography was 0.25 in group I, which was significantly lower than that (0.42) in group II. CONCLUSIONS Reconsideration of the indications for the maze procedure for AF associated with rheumatic mitral stenosis may thus be reasonable, particularly for cases in which replacement using a prosthetic valve is necessary, but we believe that patients with nonrheumatic mitral valve disease, especially those able to undergo reconstructive operations, are the best candidates for the maze procedure.

Successful surgical treatment of giant coronary artery aneurysm with fistula

Giant coronary artery aneurysm with fistula formation is a rare entity. We report a giant coronary artery aneurysm with a maximum diameter of 70 mm with fistula, in which a favorable course was obtained after surgical treatment. We also review the literature on giant coronary artery aneurysms exceeding 50 mm in maximum diameter.

Influence of Pulmonic Position on Durability of Bioprosthetic Heart Valves

BACKGROUND The insertion of bioprosthetic valves into the pulmonic position is not performed commonly because of uncertainty concerning the necessity and durability of such valves. METHODS We reviewed the long-term outcome of 10 patients who underwent pulmonary valve replacement with bioprostheses between March 1985 and March 1997. A Carpentier-Edwards supraannular bioprosthesis was used in 7 patients, a Hancock II bioprosthesis was used in 2 patients, and a Carpentier-Edwards pericardial bioprosthesis was used in 1 patient. The mean patient age at the time of pulmonary valve replacement was 38.9 +/- 16.3 years (range, 15 to 63 years). The diagnoses were pulmonary valvular regurgitation after corrective surgery for tetralogy of Fallot in 7 patients, right ventricular outflow tract stenosis and absent right pulmonary artery combined with a double-outlet right ventricle in 1 patient, pulmonary valvular regurgitation with pulmonary artery dilatation in 1 patient, and aortic valve stenosis treated with our modification of the Ross procedure using a pulmonary bioprosthesis in 1 patient. Survivors were followed up for a mean of 5 years and 5 months. RESULTS One patient underwent reoperation because of infective endocarditis of the bioprosthesis. No bioprosthetic valve dysfunction has been observed on Doppler echocardiography during a maximum follow-up period of 12.2 years, except in the patient who underwent replacement at 15 years of age. CONCLUSIONS Bioprostheses in the pulmonic position are durable in adult patients because they face a minimal hemodynamic load, but they may undergo early leaflet degeneration in younger patients.

Graft replacement for huge aneurysm of the main pulmonary artery

We present 2 cases of huge aneurysm of the main pulmonary artery without significant pulmonary artery hypertension or intracardiac shunt. Both patients underwent surgery where resection of the aneurysm and graft replacement, using Hemashield prosthesis (Meadox Medicals, Oakland, NJ), was performed. They are now leading normal lives without any symptoms.

Ten years' experience of aortic valve replacement with the omnicarbon valve prosthesis

BACKGROUND There are few clinical studies on late follow-up of the Omnicarbon monoleaflet valve. We report our 10-year experience with this valve in the aortic position and also compare late hemodynamic performance of this valve with that of the CarboMedics valve in the aortic position. METHODS From January 1985 to June 1995, 117 consecutive patients underwent aortic valve replacement (AVR) with the Omnicarbon valve. There were 66 men and 51 women aged 13 to 69 years (mean age, 50 +/- 12 years). They were divided into three groups: group 1 (43 patients) had isolated AVR, group 2 (36) had AVR and concomitant operations, and group 3 (38) had combined AVR and mitral valve replacement. Follow-up was 96.6% complete and consisted of 882.7 patient-years (range, 2.5 to 10.6 years; mean follow-up, 7.5 +/- 2.7 years). RESULTS There were three early deaths (2.6%) and 18 late deaths (2.0%/patient-year) ten of which were due to valve-related causes and eight, non-valve-related causes. Survival rates at 10 years in groups 1, 2, and 3 were 77.6%, 82.4%, and 78.6%, respectively. The overall rates of freedom from valve-related complications in groups 1, 2, and 3 at 10 years were 77.4%, 100%, and 80.9%, respectively. The rates of freedom from the following complications in groups 1, 2, and 3 at 10 years were as follows: thromboembolism--94.8%, 100%, and 89.4%, respectively; valvar thrombosis--95.0%, 100%, and 100%; anticoagulant-related hemorrhage--93.6%, 100%, and 93.4%; prosthetic valve endocarditis--93.0%, 100%, and 97.2%; and reoperation--90.6%, 100%, and 97.2%. There were no significant differences between groups. All survivors showed marked improvement in New York Heart Association functional class, from 86% in classes III and IV preoperatively to 96% in classes I and II postoperatively. The Omnicarbon valve exhibited no significant difference in hemodynamic performance after isolated AVR compared with the CarboMedics bileaflet valve at the same follow-up periods. CONCLUSIONS This 10-year study confirms that the Omnicarbon valve is a durable prosthesis and provides excellent functional improvement with low rates of thromboembolism and valvar thrombosis in the aortic position.

Redo Composite Valve Graft Replacement

Background: Redo composite valve graft replacement remains a challenging problem, that may lead to increased surgical mortality. Methods: In our experience from September 1976 through December 1999, eight consecutive patients (seven men and 1 women) underwent eight redo composite valve graft replacements. The mean age at reoperation was 43.1 years (range 31 to 51 years). Seven patients had stigmata of Marfans syndrome. Reoperation was indicated for pseudoanourysm formation in five patients, coronary ostial aneurysms in two patients, and active fungal endocarditis in one patient. Previous root replacement had been performed in all eight patients using a composite mechanical valve. The techniques used at previous procedures were the Bentall technique in seven and Carrels button technique in one. The mean interval between primary root replacement and redo root replacement was 10 years (range 2 to 18 years). The patient with active fungal endocarditis having a stuck valve was subjected to emergency operation. Results: The techniques used at the reoperations included Carrels button technique in five patients, the interposition technique (Phieler) in two patients, and Cabrols technique in one patient. Aortic arch aneurysm repair was performed in five patients. There were two hospital deaths (2 [25%] of 8). One patient died on postoperative day 1 with low cardiac output and the other suffered a sudden cardiac arrest on postoperative day 14. The mean follow‐up was 34.6 months (range 1 to 85 months). There was one late death. The cause of death was multiple organ failure due to recurrence of fungal endocarditis 6 months after redo composite and total arch replacement. Conclusion: Redo composite graft replacement can be accomplished with lower early mortality, and therefore, this operation should not be delayed given the appropriate clinical circumstances. Many causes of failure of composite valve graft replacement can be avoided if the appropriate surgical technique is chosen.

Improvement of Ischaemia-Reperfusion Injury by Lazaroid U74389G in Rat Lung Transplantation Model

The effect of lazaroid 74389G on ischaemia-perfusion injury in a rat lung transplantation model was investigated using three administration methods. In all groups, the University of Wisconsin (UW) solution was used as a flush and preservation solution at 4 degrees C, and lungs were stored for 12 h. Group I rats (controls) were not given any lazaroid treatment. In group II, lazaroid U74389G was added to the UW solution (100 micromol/l). In group III, lazaroid (10 mg/kg) was intravenously injected in the donors 30 min before lung ischaemia. Group IV received lazaroid treatment by the combined methods of groups II and III. In all the experimental groups (II-IV), recipient rats were given lazaroid (6 mg/kg) intravenously 30 min before reperfusion. Lazaroid improved the gas exchange function (groups II, III and IV), reduced the tissue lipid peroxides (group II) and ameliorated histologic lung damage (group II). The results thus seemed to be better in group II than in groups III and IV.The effect of lazaroid 74389G on ischaemia-perfusion injury in a rat lung transplantation model was investigated using three administration methods. In all groups, the University of Wisconsin (UW) solution was used as a ̄ush and preservation solution at 4°C, and lungs were stored for 12 h. Group I rats (controls) were not given any lazaroid treatment. In group II, lazaroid U74389G was added to the UW solution (100 mmol/l). In group III, lazaroid (10 mg/kg) was intravenously injected in the donors 30 min before lung ischaemia. Group IV received lazaroid treatment by the combined methods of groups II and III. In all the experimental groups (II±IV), recipient rats were given lazaroid (6 mg/kg) intravenously 30 min before reperfusion. Lazaroid improved the gas exchange function (groups II, III and IV), reduced the tissue lipid peroxides (group II) and ameliorated histologic lung damage (group II). The results thus seemed to be better in group II than in groups III and IV.

LONG-TERM RESULTS OF PORCINE BIOPROSTHESES IN THE TRICUSPID POSITION

From January 1976 to September 1994, 26 patients underwent a tricuspid valve replacement (TVR) with porcine bioprostheses (Hancock II in 19 patients, Carpentier-Edwards in 3, Hancock standard in 2, Medtronic-Intact in 1, and Liotta in 1). The mean age of these patients was 38.4 years (range, 9 to 70 years). The mean follow-up period was 6.7 years (range, 1.8 to 16.5 years). There was a complete follow-up in 100%. There were two hospital deaths and three late deaths. The actuarial survival rate at 16 years was 78.7%±8.6%. Five patients developed structural deterioration. Four of these 5 patients underwent re-TVR. The actuarial freedom rate from structural deterioration at 10 years was 47.1%±19.1%. There were no instances of thromboembolism and prosthetic valve endocarditis. Our experience indicated the major problem of the porcine bioprostheses in the tricuspid position thus to be valve durability: however, the long-term actuarial survival rate was satisfactory, including no operative morality with re-TVR due to tricuspid prosthetic structural deterioration. We therefore conclude that the choice of a porcine bioprosthesis in the tricuspid position should be considered not only for patients with isolated tricuspid valve disease, but also for the patients who have not previously received mechanical valves in the mitral or the aortic valve position.

Minimally ischemic off-pump coronary artery bypass grafting: active perfusion-assist with nitroglycerin-supplemented blood

During off-pump coronary artery bypass surgery, concern remains about possible myocardial injury associated with the transient occlusion and stabilization of the target vessels. To try to minimize myocardial ischemia and achieve hemodynamic stability, we used a coronary perfusion catheter combined with the perfusion-assisted direct coronary artery bypass system, which enables active and modified coronary perfusion of the target vessel throughout the duration of multiple grafting.

Direct-Vision Retrosternal Dissection Using the Kent Retractor for Sternal Re-Entry

Repeat median sternotomy is still associated with high morbidity and mortality from catastrophic hemorrhage or myocardial injury. To overcome these problems, we devised a new technique of sternal re-entry using the Kent retractor set (Takasago Ika Kogyo, Tokyo, Japan), which increases the safety of retrosternal dissection and sternal redivision.